\(\mu _B\)  = 1.40 MHz per gauss is the Bohr magneton, and \(m_{-2}\)  the neutrino
mass in units of \(10^{-2}\)  eV. Diagonal moments of Majorana neutrinos
must vanish, although transition moments connecting different mass
eigenstates are non-zero [1]}. Magnetic moments
could be substantially larger than Eq. (REF ) predicts.
 According to the most recent Review of Particle
Physics [2]}, the most sensitive upper bounds for \(\mu _\nu \) 
are given by the GEMMA and Borexino experiments. The GEMMA reactor
experiment [3]}
gives an upper limit \(\mu _\nu < 2.9 \times 10^{-11} \mu _B\) , and
Borexino [4]} reports upper bounds from solar neutrinos,
\(\mu _{\nu _e} < 2.8\times 10^{-11}\mu _B\) . These bounds are comparable
to the moment \(\mu _{1T}\) 
that could explain the XENON1T low-energy electron-event
excess, which does not
distinguish diagonal from transition magnetic moments.
